小柱体尺寸在线检测系统研究与实现

圆柱体零件是机械制造及各种高精度装备的核心器件,其在线高精度检测是生产质量控制的关键环节。针对圆柱体参数高精度在线实时测量展开研究,制订出在线测量的总体方案,有效控制产品的质量,调节测量系统的基准,并可有效检测各种类型圆柱体。本文主要研究了总体结构设计和轴类零件自动测量系统的硬件实现方案。     

型砂质量在线检测与控制模型的研究

型砂质量的在线控制基于两大基本前提：１．实现型砂性能的自动检测；２．寻找并建立型砂成分与性能之间的相互关系，为此，常规试验中既能反映型砂成分变化及适于在线快速检测的紧实率。水分，砂温，透气性与劈裂强度五性能被选作为在线检测项目，文中详细讨论了型砂性能在线检测仪的研制过程，诸项目的检测原理以及仪器所能达到的检测精度，由于采用了８０Ｃ５５２微处理器的控制，本仪器可在１ｍｉｎ内完成全部五项目的检测与结果     

湿型粘土砂有效粘土含量在线快速检测技术的研究

湿型粘土砂有效粘土含量在线快速检测技术的研究＊李大勇曾昕张宇彤（哈尔滨科学技术大学哈尔滨１５００８０）０引言型砂质量是影响铸件质量的重要因素，提高型砂质量控制水平的关键在于发展高效在线检测技术。国内外学者已就型砂质量在线测试系统方面作过大量研究，但其...     

淤积原理在液压系统在线污染监测中的应用

采用淤积原理的在线污染监测方法，通过检测流过滤膜某一固定体积时的压差来测量液压系统的油液污染度。研制出在线监测装置，采用电磁铁推动活塞吸油和获得压降，步进电机带动自制金属滤膜旋转实现过滤与反向冲洗功能，利用虚拟仪器软件LabVIEW设计监控平台，并对在线污染监测方法进行了理论分析与实验研究。实验结果表明，在线污染监测方法能给出ISO、NAS与SAE油液污染等级，可满足生产现场的在线监测要求。     

谐振式音叉密度测井方法与检测电路设计

在油井动态监测过程中,人们根据井下流体密度,辅以持水率和流量信息,可以计算出油井中不同层位的油、气、水分相产量,为地层资源评价、井下施工作业提供及时准确的依据。因此,井下流体密度的在线测量具有重要的意义。根据音叉传感器的谐振频率与音叉叉体上所粘附的液体的密度之间具有单调的函数关系,提出了一种谐振式音叉密度测井方法与检测电路设计。该方法不仅测量范围广(0.80～1.20 g/cm~3),而且测量精度高(±0.03 g/cm~3),可以满足油田实际生产测井过程中对井下混合流体密度测量的要求。     

基于计算机技术的工序质量控制系统研究

针对企业设备陈旧、加工手段落后致使产品质量不高的状况，在分析工序质量控制观念、方法的基础上，提出了应用计算机技术进行在线控制的构想。对控制系统运行所依据的数理统计理论及控制方法与计算机技术结合的可行性进行了分析。以经济实用性、现场可操作性为出发点，将计算机技术、在线检测技术、传感技术、网络与数据库技术及质量控制方法相结合，使所开发出的系统能够实现在线工序质量控制。该系统可用于对单工序、多工序及区域性的质量控制并可对工序质量及系统自身进行可靠性分析和经济性分析。     

焊接质量在线检测方法分析

随着现代焊接生产的发展,传统的人工质量检验方法生产效率低、检验误差大、人工成本高等诸多问题越加凸显,对此应积极利用自动化、智能化技术,开发焊接质量在线检测系统,提高焊接质量检测效率、精确性等。本文首先分析了焊接质量在线检测方法的提出背景,并具体论述了几种焊接质量在线检测方法及其原理,最后以红外在线检测方法的应用为例展开探讨,验证了其应用的有效性与可行性。     

精密复杂零件数控加工在线检测方法研究

对精密复杂零件数控加工在线检测原理进行了介绍,对在线检测路径进行了规划,并在此基础上建立了在线检测宏程序库。给出了精密复杂零件数控加工在线检测宏程序库基本指令、用户变量与检测实例,并通过试验进行了验证。     

生料球粒度在线检测方法研究

水泥窑生料球粒度大小对水泥质量具有直接影响,目前尚无生料球粒度在线检测手段。本文基于计算机图象识别技术,提出一种在线测定生料球粒度的新方法,解决了料球图象识别的关键问题——料球的边缘检测。并以此组成生料球粒度在线检测系统,其输出可作为现有生料球预加水控制系统的反馈信号,以便实现闭环控制。对比实验表明,系统给出的粒度分布及平均粒度与实际粒度分布及平均粒度基本吻合。     

热轧螺纹钢在线图象检测技术的研究

本文介绍了利用计算机图象系统对具有复杂轮廓的热轧螺纹钢进行在线检测的技术。提出了用可控频闪光源照明和面阵ＣＣＤ成象方式获取高速运动体的清晰图象，设计了新的图象处理算法，能同时给出热轧螺纹钢的多个参数。实验证明测量具有高的精度，可有效实现螺纹钢的在线检测。     

On the modeling of a piezoelectrically actuated microsensor for simultaneous measurement of fluids viscosity and density

This paper deals with the analysis of a novel micro–electro-mechanical (MEM) fluid density and viscosity sensor. The proposed sensor consists of a micro-beam and a sensing micro-plate immersed in a fluid. In order to actuate longitudinally the micro-beam and micro-plate, the sensor includes a pair of piezoelectric layers bonded to the upper and lower surfaces of the micro-beam and subjected to an AC voltage. The coupled governing partial differential equations of longitudinal vibration of the micro-beam and fluid field have been derived. The obtained governing differential equations with time varying boundary conditions have been transformed to an enhanced form with homogenous boundary conditions. The enhanced equations have been discretized over the beam and fluid domains using a Galerkin based reduced order model. The dynamic response of the sensing plate for different piezoelectric actuation voltages and different exciting frequencies has been investigated. The effects of viscosity and density of fluids and geometrical parameters of the sensor on the response of the sensing plate have been studied.     

气体对磁流体动力学传感器影响机理的探讨

由于气体和导电流体性质上的差异,导电流体中气体的存在将对磁流体动力学(MHD)传感器的输出特性产生影响。基于电磁感应理论和两相流理论,文章推导并建立了导电流体中含气体的MHD传感器VOF模型。通过ANSYS Fluent对含气体的MHD传感器输出特性进行仿真分析,同时搭建试验平台对不同气体含量MHD传感器进行试验验证。结果表明,导电流体中的气泡在低频时容易被拉伸撕裂成小气泡并随着角振动分散,同时使得流体环流场和电场产生偏移和畸变,角振动频率越低,此现象越明显;当导电流体中不含气体时角振动频率和幅值、重力加速度及偏心等外部因素对MHD传感器的输出特性无影响;当导电流体中含有气体时,MHD传感器的输出特性畸变等随气体含量、重力加速度和偏心的增大而增大,随角振动频率和幅值的增大而减小。文章研究成果能够为MHD传感器导电流体灌装工艺控制提供指导,有助于MHD传感器精度和稳定性的提升。     

悬吊结构体系摆振响应测试及非线性误差修正

为解决悬吊结构多种模式摆振运动状态的量测问题,采用基于加速度测量原理的倾角传感器,通过理论分析建立了由传感器加速度信号提取平动运动模式下结构摆角增益系数的计算公式,解决了结构平动运动模式的量测问题,并且经过非线性误差修正后可以提高测量精度。对于结构转动(或回转)运动模式,类似于平动摆振运动控制系统在转动中由于质量振子的线性位移与结构摆角速度耦合影响而导致控制失效的问题,此时基于加速度原理的倾角传感器也将失效,而需要采用陀螺仪测量回转运动摆振角速度,再通过积分计算结构摆角。最后,对悬吊结构体系在两种运动模式下的摆振运动状态测量进行了试验验证,结果充分证明了本文所提方法的有效性和可行性。此外,针对悬吊结构复杂的多模式平转耦联摆振状态测量,提出需要将倾角传感器与陀螺仪相结合的监测策略。     

Effects of gas composition on asynchronous error motion in externally pressurized spindles

Stable, externally pressurized aerostatic spindles exhibit picometer-level vibration as a result of the interaction of the high-pressure working fluid and its path through a spindle's compensation features (e.g., grooves, orifices, pockets, etc.). This vibration presents a challenge as end users seek the lowest possible asynchronous error motion in manufacturing, metrology and data storage applications. This technical brief describes experimental testing to quantify this low-level vibration and its significant variation with both supply gas composition and pressure. Of the gases tested, helium and neon generate the lowest vibration while other gases including air lead to an order of magnitude higher vibration. Vibration levels with carbon dioxide and nitrous oxide are an additional order of magnitude higher. At present, the root cause of the vibration amplitude dependence on supply gas composition is unknown although kinematic viscosity and mean free path length correlate well with the results presented here.     

A study of mass flow rate measurement based on the vortex shedding principle

Mass flow rate measurement is very important in the majority of industry processes because the mass of fluid is not affected by ambient temperature and pressure as the volume will be. Conventional mass flow rate is normally derived from the volumetric flow rate multiplied by fluid density. The density can be obtained by a densitometer or calculated according to the temperature and pressure measured by a thermometer and pressure gauge respectively. However the measurement accuracy is not always satisfactory. Flowmeters directly measuring mass flow rate have been studied and developed recently, such as Coriolis and thermal flowmeters. Unfortunately they still have some limits in practical applications. A new method in which mass flow rate can be directly measured based on the vortex shedding principle is presented in this paper. As a vortex flowmeter, von Kàrmàn vortex shedding is generated by a bluff body (vortex shedder), leading to a pressure drop and pressure fluctuation. A single differential pressure sensor is employed to detect the pressure difference between upstream and downstream sides of the vortex shedder. Both vortex shedding frequency and pressure drop are contained from the output signal of the differential pressure sensor, so that the mass flow rate can be obtained from the pressure signal. Numerical simulation has been done to analyze the characteristics of the fluid field and design the measurement device. The Computational Fluid Dynamics (CFD) codes Fluent were used in the numerical simulation. Experiments were carried out with water and gas, and the results show that this method is feasible and effective to measure the mass flow rate. This method has also robustness to disturbances such as pipe vibration and fluid turbulence.     

On the Mathematical Modeling of a MEMS-Based Sensor for Simultaneous Measurement of Fluids Viscosity and Density

This paper discusses a novel microelectromechanical sensor for simultaneous measurement of fluids viscosity and density. Its operation is based on a longitudinal piezoelectric actuation of a micro-beam in a laminar fluid field. The proposed sensor consists of a micro-beam and a micro-cylindrical sensing element immersed in a fluid. In order to actuate the sensor longitudinally, the micro-beam is bonded with two piezoelectric layers on its upper and lower surfaces which are subjected to an AC voltage. The coupled governing partial differential equations of the micro-beam and fluid field have been derived. The obtained governing differential equations with time-varying boundary conditions have been transformed to an enhanced form with homogeneous boundary conditions. The enhanced equations have been discretized over the beam and fluid domain using Galerkin based reduced order model. The dynamic response of the sensing element for different piezoelectric actuation voltages and different exciting frequencies has been investigated. The effects of viscosity and density of fluids and geometrical parameters of the sensor on sensing element response have been studied.     

传感器支架振动对扭振测量的影响及消除方法

通过实验研究确定了传感器支架振动对扭振测量有较大影响,且由整机振动引起。从磁电传感器电压特性出发,以传感器支架振动影响下的传感器输出电压和瞬时转速表达式为基础,阐明了作用机理;同时研究了支架振动引起伪扭振信号的规律及频谱特征。研究表明,支架振动引起的伪扭振信号随着支架振动幅值的增加而增加;伪扭振信号的主要成分是支架振动的阶数及其二阶;所取基准电压越接近0,伪扭振信号幅值越小。提出了一种基于最佳基准电压的去除支架振动影响的新方法,并提出了最佳基准电压的计算方法。仿真研究表明,该方法是有效的,为改善扭振测量精度提供了理论依据,具有工程应用价值。     

磁流变液悬置用于发动机隔振模糊控制

设计了一种基于圆盘挤压模式磁流变悬置,利用试验方法得出了不同激励频率条件下磁流变悬置的循环耗散功与励磁电流的关系.利用磁流变悬置,建立了发动机振动半主动控制的研究模型.提出了一种模糊控制方法,利用转速、加速度和动态拉压力传感器,借助美国国家仪器公司的数据采集和实时控制器,构建了发动机隔振模糊控制试验系统,并开展了怠速和常用工况条件下的发动机振动隔离控制试验研究.研究结果表明,与橡胶悬置相比,基于磁流变悬置的模糊控制系统,能够降低发动机动态激振力传递到支承,并且低转速条件下的振动隔离效果优于高转速条件下的.     

基于PSD的旋转机械振动传感器

研究了基于二维光位置敏感探测器(position sensitive detector,简称PSD)的激光振动传感器,重点介绍了PSD的结构、位置和振动检测原理,给出了位置坐标函数表达式和相应的输出信号检测电路框图,分析了影响该传感器检测精度的因素,提出了相应的解决办法,提供了传感器检定数据和实测振动波形。试验结果表明,该传感器各项性能指标完全满足旋转机械轴振测量要求,为旋转机械振动提供了一种新的可靠测量方法。     

工件表面质量检测中高速图像采集技术研究

针对工件表面质量在线检测过程中的高速图像采集环节,提出了一种工件图像高速采集方法。分析了图像采集中定位精度、运动模糊、曝光时间和工件运行速度之间的定量关系,研究了传送机构与工件表面的振动对图像采集的影响,设计了图像采集时序。利用光电传感器实现工件的快速触发,使用高精度延时模块实现工件的准确定位,通过减小曝光时间控制运动模糊。基于高速采集方法设计了高速图像采集系统,定位精度小于0.1mm,运动模糊小于1pixel,保证了工件的准确定位和图像的清晰度,有效保证了工件表面质量检测。